CLi on top is covering for class CSS
When you have active CLI on top, and you click the "crosshair" icon on a class, a switch to stylesheet (or just change the left side panel, where you have no more the class) ... you can't close the CSS window as it's covered with CLI. You have to close CLI in order to do so.
Just somethign to think about.
PS : I run into this quite often, as ocasionally I do a class, which later on I realize I want only for certain breakpoints and I'm writing it manualy in stylesheet. And in order to save some time, I click on the crosshair in order to coppy the CSS and then just modify the "@media"